I had a warranty issue on my v70 D5 and through not being on the ball I allowed the miles to go to 60050 thinking that the main dealer would be reasonable , they wouldnt look at it without being paid , they advised me that 1 mile over 60k and thats your lot . My car has 126k on the clock now and the top engine mount has been knackered for a long time but the symptons are not as bad as you describe just a slight clonking now and again and mine is completely detatched , its asking for trouble putting extra strain on the bottom engine mounts but have lots of other repairs having more priority so I drive very carefully and try not to accelerate or brake much , what you describe sounds much worse , if I had the car I would be back at the main dealer insisting they do something about it . Your warranty is worth a real amount of money , I personally didnt appreciate the value of it until it was gone , dont leave it too late .